Switchable hydrostatic adjusting device

Patent metadata

Field	Value
Publication number	US-9932957-B2
Application number	US-201514678418-A
Country	US
Kind code	B2
Filing date	Apr 3, 2015
Priority date	Apr 3, 2014
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

Hydrostatic adjusting device of a hydraulic machine, the swept volume of which can be adjusted by way of a servo adjusting unit, having a control unit which has a control cylinder which has at least one inlet for pressurized hydraulic fluid, at least one servo connector for a connecting line to the servo adjusting unit, and at least one outlet to a hydraulic fluid collecting region. A control piston is arranged in the control cylinder, which control piston can be displaced by means of at least one control piston actuator and has control edges. In interaction with control edges which are configured in the control cylinder, the inlet or the outlet can be alternately connected hydraulically to the connecting line, whereby the pressure which prevails in the connecting line can be returned hydraulically via a control line to at least one end side of the control piston.

First claim

What is claimed:

1. Hydrostatic adjusting device ( 8 ) of a hydraulic machine ( 1 ), the swept volume of which can be adjusted by way of a servo adjusting unit ( 9 ), having a control unit ( 10 ) which has a control cylinder ( 17 ) which has at least one inlet ( 24 ) for pressurized hydraulic fluid, at least one servo connector ( 25 ) for a connecting line ( 16 ) to the servo adjusting unit ( 9 ), and at least one outlet ( 26 ) to a hydraulic fluid collecting region ( 27 ), a control piston ( 18 ) being arranged in the control cylinder ( 17 ), which control piston ( 18 ) can be displaced by means of at least one control piston actuator ( 21 ) and has control edges ( 39 ), as a result of which, in interaction with control edges ( 38 ) which are configured in the control cylinder ( 17 ), the inlet ( 24 ) or the outlet ( 26 ) can be alternately connected hydraulically to the connecting line ( 16 ), and wherein a prevailing pressure in the connecting line ( 16 ) is returned hydraulically via a control line ( 32 ) to at least one end side ( 19 , 20 ) of the control piston ( 18 ), characterized in that the control line ( 32 ) can be opened and closed by means of a load response valve ( 30 ).

2. Hydrostatic adjusting device according to claim 1 , characterized in that the load response valve ( 30 ) can be actuated pneumatically, hydraulically, electrically or mechanically.

3. Hydrostatic adjusting device according to claim 1 , characterized in that the load response valve ( 30 ) can be moved in a variable manner into switching positions, in which a passage for hydraulic liquid in the control line ( 32 ) is only partially open.

4. Hydrostatic adjusting device ( 8 ) according to claim 1 , characterized in that the control line ( 32 ) and the load response valve ( 30 ) are integrated into the control unit ( 10 ), in particular into the control piston ( 18 ).

5. Hydrostatic adjusting device ( 8 ) according to claim 1 , characterized in that, in order to actuate the load response valve ( 30 ), the at least one control piston actuator ( 21 ) acts on a slide ( 53 ) of the load response valve ( 30 ), which slide ( 53 ) is arranged within the control piston ( 18 ), the control piston actuator ( 21 ) first of all switching the load response valve ( 30 ) in the case of activation before the control piston actuator moves the control piston ( 18 ).

6. Hydrostatic adjusting device ( 8 ) according to claim 1 , characterized in that a branch ( 34 ) from the control line ( 32 ) is provided in the control line ( 32 ) upstream or downstream of the load response valve ( 30 ), from which branch ( 34 ) a discharge line ( 37 ) leads to a hydraulic fluid collecting region ( 27 ) of the hydraulic machine ( 1 ), a back-pressure orifice plate ( 35 ) being arranged in the discharge line ( 37 ).

7. Hydrostatic adjusting device ( 8 ) according to claim 6 , characterized in that a throttle ( 33 ) is arranged in the control line ( 32 ).

8. Hydrostatic adjusting device ( 8 ) according to claim 6 , characterized in that the back-pressure orifice plate ( 35 ) and/or the throttle ( 33 ) are/is temperature-independent.

9. Hydrostatic adjusting device ( 8 ) according to claim 6 , characterized in that the back-pressure orifice plate ( 35 ) and/or the throttle ( 33 ) are/is integrated into the load response valve ( 30 ).

10. Hydrostatic adjusting device ( 8 ) according to claim 6 , characterized in that the back-pressure orifice plate ( 35 ) and the pressure-reducing orifice plate ( 33 ) are exchangeable and/or adjustable.

11. Hydrostatic adjusting device ( 8 ) according to claim 1 , characterized in that the servo adjusting unit ( 8 ) has two servo chambers ( 13 ), and each servo chamber ( 13 ) is assigned in each case one connecting line ( 16 ) with an associated control line ( 32 ), which lead in each case to opposite end sides ( 19 , 20 ) of the control piston ( 18 ).

12. Hydrostatic adjusting device ( 8 ) according to claim 11 , characterized in that each end side ( 19 , 20 ) of the control piston is assigned a control piston actuator ( 21 ), it being possible for each control line ( 32 ) to be opened and closed at least partially by the control piston actuator ( 21 ) which is arranged on this side independently of the other control line ( 32 ).

13. Hydrostatic adjusting device ( 8 ) according to claim 1 , characterized in that the control edges ( 39 ) of the control piston ( 18 ) exhibit a positive or negative overlap with the control edges ( 38 ) of the control piston ( 18 ) in a neutral position of the said control piston ( 18 ) in the control cylinder ( 17 ).

14. Hydrostatic adjusting device ( 8 ) according to one of the preceding claims, characterized in that the control unit ( 10 ) has a position return device ( 40 ) which is coupled to an adjusting element ( 41 ) of the hydraulic machine ( 1 ) and the control piston ( 18 ) and moves the control piston ( 18 ) into the neutral position after the desired deflection of the hydraulic machine has been achieved.

15. Hydrostatic adjusting device ( 8 ) according to claim 13 , characterized in that the force level of the position return device ( 40 ) of the servo adjusting unit ( 8 ) can be varied.

16. Hydraulic machine ( 1 ) having a hydrostatic adjusting device ( 8 ) according to claim 1 , characterized in that the hydraulic machine ( 1 ) can be operated in an open or closed hydraulic circuit.

17. Hydraulic machine ( 1 ) having a hydrostatic adjusting device ( 8 ) according to claim 1 further comprising a blind bore ( 51 ) which is arranged at a first end of the control piston ( 18 ) in the axial direction of the control piston ( 18 ) and the bottom ( 57 ) of which has a further bore ( 52 ), and a radial duct ( 58 ) which is through-connected to the blind bore ( 51 ), a slide ( 53 ) being arranged within the blind bore, which slide ( 53 ) has an axial longitudinal bore ( 54 ) and a radial transverse bore ( 55 ) which is through-connected to the longitudinal bore ( 54 ), and which slide ( 53 ) is arranged such that it is prestressed against the bottom ( 57 ) by way of a valve spring ( 36 ) and can be displaced axially in such a way that, if the slide ( 53 ) is not loaded in the direction of the bottom ( 57 ), there is a through-connection between the radial bore ( 55 ) and the radial duct ( 58 ), wherein the through-connection is configured to be opened or closed by way of an axial displacement of the slide ( 53 ) in the direction of the bottom ( 57 ).

Assignees

• Danfoss Power Solutions Gmbh & Co Ohg

Inventors

• Thoms Reinhardt
• Wuestefeld Martin

Classifications

• F15B2211/20553

  with pilot circuit, e.g. for controlling a swash plate · CPC title

• F03C1/005 Primary

  motor piston stroke control · CPC title

• F15B11/0423

  by controlling pump output or bypass, other than to maintain constant speed · CPC title

• F15B2211/6658

  Control using different modes, e.g. four-quadrant-operation, working mode and transportation mode · CPC title

• F16H61/475

  for achieving a target power, e.g. input power or output power · CPC title